Once thought to exceed 20,000 in number, S. oerstedti is facing
serious conservation concerns in Central America. The estimated
population of the Panamanian S. o. oerstedti is 2000
individuals while only 1500 S. o. citrinellus are thought to
remain (Cropp & Boinski 2000). Unfortunately, there are no
population estimates for S. vanzolinii and little published
information about its conservation issues and future viability.

CONSERVATION THREATS & POTENTIAL SOLUTIONS

Threat: Human-Induced Habitat Loss and Degradation

In Costa Rica, squirrel monkeys are threatened because of increased
rates and amounts of deforestation and forest fragmentation and
infrastructure for the country's booming tourism industry. In Panama,
they have fared even worse as deforestation has been rampant and
virtually unregulated (Boinski & Sirot 1997; Boinski et al. 1998).
The development of agribusinesses
for oil palm and banana plantations is a serious component of habitat
destruction and fragmentation. Squirrel monkeys rarely come to the
ground, travel primarily on branches between one and two centimeters in
diameter, and will not leap horizontally between trees if the distance
is greater than two meters. Logging roads, clearings for telephone and
electric power lines, or other practices leading to forest fragmentation
restrict populations to smaller areas of forest, decreasing their
ability to find food during times of year when food abundance is lowest
and leading to a host of genetic
diversity issues that could affect their conservation (Boinski et
al. 1998).

Fortunately, Costa Rica exhibits among the highest conservation
sophistication and largest proportion of protected lands in Central and
South America; squirrel monkeys are protected at two reserves, Corcovado
and Manuel Antonio National Parks (Cropp & Boinski 2000).
Ironically, in protected parks where disturbance such as selective logging, clearing for swidden agriculture, and other sustainable
disturbance regimes are prohibited, successional growth of secondary forests has resulted in an
abundance of primary forest. This
is specifically problematic for squirrel monkeys because they prefer
secondary growth forests and will not use primary forests because of the
low abundance of arthropods, fruits, and flowers compared to disturbed
forests (Boinski et al. 1998).

Potential Solutions

Ecotourism in Costa Rica is focused on the unique fauna and flora of the
country and is the largest source of foreign currency revenues (Boinski
et al. 1998). Tourism proprietors should be enlisted to assist in
conservation strategies revolving around squirrel monkeys in their
areas, specifically to develop their operations responsibly with minimal
habitat fragmentation.

In protected areas, management should be a focus of the Costa Rican
government. In a pristine forest, natural disturbances such as
hurricanes and floods would initiate the secondary forest regeneration
process. When these types of habitats are not available, in an intact
forest, squirrel monkeys would move to another adjacent area that may
have secondary forest. Maintaining some areas of secondary successional
growth within protected areas, or even better, protecting more adjacent
lands surrounding Corcovado and Manuel Antonio would provide more
suitable habitat for squirrel monkeys in these areas (Boinski et al.
1998).

Threat: Harvesting (hunting/gathering)

Squirrel monkeys are subject to capture and sale as pets in both
domestic and foreign markets. One study revealed that in addition to
being easy to obtain and frequently smuggled out of the countries of
origin, squirrel monkeys are sold for an alarmingly low price,
US$30-50 (Boinski et al. 1998).

Potential Solutions

The trade in squirrel monkeys could potentially be decreased through
education programs and alternative income opportunities. Since ecotourism in
Costa Rica centers on the unique animal and plant resources in the
country, preserving these resources should be a priority to all those who benefit
economically from tourism profits. Encouraging tourism operations to
staff their outfits with local people will increase the sense of
ownership for local populations and will give them direct economic
benefit from preserving squirrel monkeys.

Threat: Accidental Mortality

One artifact of development of infrastructure for tourism includes power
lines, for both electricity and telephone service. The leading cause of
accidental mortality among squirrel monkeys is electrocution as they use
power lines to move between patches of forest fragments (Boinski et al.
1998).

Potential Solutions

Better insulation on power lines would decrease the number of accidental
deaths by electrocution, but another consideration is that squirrel
monkeys use power lines to move between forested areas where natural
corridors are not available. In addition to better insulation,
maintaining branches that hang over roads and allowing the monkeys to
use these to move across roads would increase mobility between fragments
as would maintenance of brushy areas below power lines (Boinski et al.
1998).

Threat: Persecution

Where they exist near human settlements practicing small-scale
agriculture, squirrel monkeys are occasionally hunted as pests because
they often raid and destroy fruit crops, but this persecution is not
nearly as serious as other threats facing squirrel monkeys (Boinski et
al. 1998).

Potential Solutions

Landowner education about the extreme rarity of these squirrel monkeys
might begin to change attitudes towards them and their crop-raiding
behaviors, though no work has been done to decrease hunting of squirrel
monkeys in this area.

Threat: Pollution

There is little direct evidence of squirrel monkey mortality from
pollution, but in forests neighboring oil palm and banana plantations,
where pesticides are used liberally, poisoning of squirrel monkeys could
potentially be a serious threat to small populations. There have been
reports of golden lion tamarins (Leontopithecus rosalia) that
died after ingesting insects contaminated with pesticides (Pissinatti et
al. 2002).

Threat: Natural Disasters

While hurricanes cause natural disturbances to primary forest that
create the secondary growth forest preferred by squirrel monkeys, the
hurricane itself can inflict great direct damage to the monkeys. In
1999 a hurricane was likely the responsible for the death of two-thirds
of the main troop in Manuel Antonio National Park (Boinski & Sirot
1997).

Threat: Changes in Native Species Dynamics

Nocturnal predation in protected areas with intact predator populations
may have an effect on squirrel monkeys. To minimize the chance of
predation, squirrel monkeys sleep at the edges of palm fronds and in the
case of disturbance, drop to the ground (Boinski & Sirot 1997). By
sleeping at the edge of the branches, they decrease the number of
predators that can reach them; palm fronds cannot support much weight,
so any predator attempting to reach a sleeping squirrel monkey will
likely cause disruption and the monkeys will drop to the ground and
avoid predation.

Potential Solutions

Wildlife managers could supplement squirrel monkey habitat with sleeping
sites that are predator-resistant to decrease the chance of predation
and maintain the stability of squirrel monkey populations in some areas
(Boinski & Sirot 1997).

Threat: Intrinsic Factors

The limited dispersal options for young, sexually maturing females may
have effects on the viability of offspring born to closely related
relatives. If females are restricted from emigrating because their natal group is in a forest fragment,
the only option is to breed with males that are potentially their
relatives (Boinski & Sirot 1997). Inbreeding can lead to a host of
problems including inbreeding
depression, genetic drift, and
low levels of genetic diversity that are potentially serious threats to
small populations of squirrel monkeys.

Potential Solutions

It should be a priority to maintain secondary growth forests in
protected areas where squirrel monkeys are found in addition to
increasing protected areas so that forests are more contiguous rather
than fragmented. Corridors connecting habitat fragments may help
dispersing females find new groups into which they can assimilate and
mate.

Threat: Human Disturbance

One of the serious concerns about S. oerstedti conservation is
the hesitancy of officials, especially in Costa Rica, to direct funding
towards conservation initiatives because of the common belief that it is
an introduced species to the area (Boinski et al. 1998; Cropp &
Boinski 2000). With so few funds and a serious conservation crisis in
this hotspot of biodiversity, it
is politically unpopular to attempt gallant conservation efforts on a
species thought to have been introduced by humans before the arrival of
European settlers. This is particularly unfortunate because molecular
genetic evidence proves the species distinction between S.
oerstedti and other squirrel monkeys, and the population of both
subspecies is dwindling to critically low numbers (Cropp & Boinski
2000).

Potential Solutions

Changing public attitudes towards squirrel monkeys in Costa Rica will
likely engender specialized efforts to conserve this endemic resource. With additional
data becoming available to prove their status as non-introduced species,
perhaps the process of changing attitudes will quicken and focused
conservation activities will become more of a priority for the Costa
Rican government and non-governmental organizations.

SPECIAL NOTES

Captive breeding programs of S. oerstedti are nonexistent in
the United States. There are two breeding colonies in Costa Rica that
have been maintained through animals seized in the pet trade, but as of
1997, there were only three individuals kept at the Phoenix Zoo (Boinski
& Sirot 1997). While other species of squirrel monkeys are well
represented in the captive population, problems with hybridization occur because of the
changing taxonomic status and inattention to subspecific variation.
Furthermore, the founder animals which started the breeding colonies may
have been misclassified, making it impossible to differentiate between
the species-type of current populations (Schreiber et al. 1998). The
taxonomic categorization of captive populations of squirrel monkeys is
confusing and not likely to be resolved without genetic testing;
nonetheless, animals of questionable taxonomic status can be used in
displays at zoos and for educational purposes, regardless of their
pedigree.

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